1. Field of the Invention
The invention herein relates to a hand held garden tool and more specifically to a class of garden tool that is intended to assist in removing unwanted plants.
2. Overview of Prior Art
Since the beginning of time, mankind has been plagued with the competition of unwanted plants in relation to desirable plants with regard to water, nutrients and sunlight. As such, long ago tools were created to assist in the task of removing the unwanted plants to aid in the growth of the desirable plants. In the most basic form, the desirable plants produce food for the person who tilled the soil, aiding in their survival, but also ornamental displays such as lawns, playing fields and flower gardens benefit from agron cultivation.
Various attempts in the form of tools have been made to assist in this process of tilling the soil. The most traditional includes a hoe. This tool includes a blade that is capable of striking the soil and penetrating its surface, cutting the roots of the unwanted plants and allowing the soil to be "turned over" onto the plants, suggesting their demise. Two problems exist. First, the physical work required to move the mass of the soil accompanied with the work of "chiseling" the soil loose is excessive and unnecessary. This results in great energy expenditure by the user, resulting in minimal time at task before becoming physically tired and forced to stop.
The second problem is when the hoe is brought down slicing the ground in a substantially vertical orientation, many of the roots of the plants may be left undamaged, and left to grow back. The result is extra work to do a less than adequate job. Much of the prior art reflects this level of function or more accurately the lack of function. The first of which is disclosed by Lucan in U.S. Pat. No. 3,952,812. Here a traditional blade of a hoe is accompanied by a tool intended to pull weeds.
In a similar fashion, Voss disclosed in U.S. Pat. No. 4,377,211 a hoe with a curved blade and a hooked cutting edge. The limitations are previously disclosed are apparent here as well.
A curb weeder is disclosed by Albertson in U.S. Pat. No. 4,546,831 in which the functions and limitations of the previously disclosed are consistent with the exception that the blade of this device is of a minimal size and cupped for use on small areas such as the cracks of sidewalks and therefore not functional in an open area as a hoe would typically be used.
Another device that was disclosed was by Parker in U.S. Pat. No. 4,334,583. Here a shovel like device is disclosed that is intended to perform many functions pertaining to yard work. The blade is substantially flat to the longitudinal handle and therefore this makes the device function more as a shovel than a hoe with regard to tilling the soil, but the limitations as discussed still apply in that soil would typically be uprooted and turned after every digging stroke.
A trenching tool was disclosed by Lee in U.S. Pat. No. 3,782,770 in which a narrow shovel head is used where the angle between the shovel head base and the longitudinal handle is less than 180 degrees. This device includes a shovel head that is intended to scoop and hold soil thereon. Such a device would be of minimal value as a weeding device for the reasons already disclosed. In addition, the handle of this and all of the formerly disclosed are longitudinal in form. This works fine for carrying an item, but to apply a pushing force to a handle of this design, as would be desirable in a weeding tool, would be very inefficient.
The handle issue was addressed by Gabriel in U.S. Pat. No. 4,865,372 in which a shovel-like apparatus was disclosed including bicycle-like handle bars that are attached to a longitudinal member which is in turn mounted to a type of shovel head. Handle bars of this type are useful when pushing the shovel head such as when shoveling snow or other material that can be "dozed" and lifted. Here both hands can be placed side by side, allowing for an effective transfer of force from the user to the device with minimal twist on the user's spine. The twist is what puts the user's spine in a precarious position by being susceptible to injury from applied force. Though the disclosed device does address this issue it is not suitable for slicing under soil due to the size, weight and complexity of the shovel head.
Disclosures that are directed to slicing under the soil to kill unwanted plants are very limited. One device was disclosed by Buchanan in U.S. Pat. No. 3,604,518. Here a triangular base is fastened to a longitudinal handle by two vertical risers attached to the triangular base. The device is pulled or pushed just below the surface of the ground to destroy the roots of the unwanted plants. Problems include guiding or steering the device and the inefficient method of power transmittal by use of a longitudinal handle as previously supported.
The disclosure by Page in U.S. Pat. No. 5,390,746 shows a longitudinal support with a handle on one end and a flat blade on the other end. As previously, the blade is adapted to penetrate the surface of the soil and destroy the root system of the unwanted plants with minimal energy expenditure by the user. The handle is simply a longitudinal rod positioned substantially parallel to the blade. A grip is included on the longitudinal support to assist in grasping the longitudinal portion with one of the user's hands, while the other is on the handle.
The device is an improvement over much of the art in regard to the task of weeding, but guiding or steering the blade would still be difficult at best especially in soil that includes a fair amount of weed roots, but the biggest problem is stress on the user's back. Because of the position of the user's hands on the device, the user's body must be rotated when applying force in a forward manner. This results in a torsional load on the user's spine and reduces the ability to apply force to the device to do work.
In the realm of hand held weeding tools, numerous disclosures exist that are intended to remove a single weed and its root system at a time. Such disclosures include Lee, Green, Plecki and Hostetter in U. S. Pat. Nos. 5,244,241; 5,188,340; 5,060,997 and 4,456,075 respectively. Each if these devices includes a substantially linear shank each with some type of hook or blade structure mounted thereto. The devices vertically penetrate the soil next to a plant and allow for rotation to secure the root of the plant so that the user can then extract the plant and root from the soil. Such devices are not functional on large areas because of the time requirement to extract each plant, one at a time, and they are only of value on larger plants, typically broadleaf type plants, and not effective on grasses.
Finally, a type of lever devices for removing plants were disclosed by Combs, Townsend, Jr. and Vernon, et al. in U.S. Pat. Nos. 4,779,685; 5,257,666 and 4,790,585 respectively. Here the common denominator includes a longitudinal lever in the form of a handle with one end adapted to penetrate the soil. The benefit to such a category of weed pullers is that, in many cases, great forces can be transferred by the user to extract a plant. The inadequacy is that it is slow, again because of the limitation of displacing only one plant at a time. In many cases a large area needs to be worked and small grasses and weeds are the biggest concern. The large plants can be extracted one at time by hand if necessary, because there are usually few of them, otherwise motor powered implementation is relied upon.